EP3460243A1 - Membrane pump with reliable membrane layer control - Google Patents

Abstract

The present invention relates to a diaphragm pump (1) having a delivery chamber (3) and a working chamber (5), wherein the working chamber is filled or filled with a hydraulic fluid and is in operative connection with a pressure generating device in order to apply an oscillating pressure to the hydraulic fluid. further comprising
a membrane (11) having at least one membrane layer (13) and a membrane core (15) which separates the delivery space (3) and the working space (5), the membrane (11) having a membrane return device (17) comprising a tie rod (15) 19) can be brought into operative connection, which can act on the membrane (11) in the direction of the suction stroke position with a return force and further comprising a reservoir (21) for receiving the hydraulic fluid, and wherein the working space (5) and the Reservoir (21) by means of a closure element (23) closed return flow channel (25) are interconnected, and wherein the closure element (23) with the membrane core (15) and the membrane retractor (17) is in operative connection, so that the return force and a by the fluid pressure in the working space (5) of the return force counteracting pressure force on the closure element (23) acts, and wherein when a predetermined Au exceeded Slackening force as the sum of the return force and the pressure force on the closure element (23) of the return flow channel (25) is opened.

Description

The present invention relates to a diaphragm pump with a functionally reliable diaphragm position control.

Diaphragm pumps have a delivery chamber with a suction connection and a pressure connection and a working space which is separated from the delivery chamber by a membrane. In order to convey a medium, the membrane is oscillated between a first and second position back and forth, in which the working space is filled with a hydraulic fluid, which is acted upon by an oscillating pressure. The two positions of the membrane are usually referred to as Druckhubposition and as suction stroke position.

The pressure connection is usually connected to the delivery chamber via a pressure valve designed as a check valve and the suction connection is connected to the delivery chamber via a suction valve which is likewise designed as a check valve. During the movement of the diaphragm from the first to the second position, the so-called suction stroke, the volume of the delivery chamber is increased, as a result of which the pressure in the delivery chamber drops. As soon as the pressure in the delivery chamber falls below the pressure in a suction line connected to the suction connection, the suction valve opens and the medium to be conveyed is sucked into the delivery chamber via the suction connection. As soon as the diaphragm moves from the second position back to the first position (this is the so-called pressure stroke), the volume in the pumping chamber decreases and the pressure in the pumping chamber rises. The suction valve is closed to prevent backflow of the medium to be pumped into the suction line. As soon as the pressure in the delivery chamber exceeds the pressure in a pressure line connected to the pressure connection, the pressure valve is opened so that the delivery medium located in the delivery chamber can be pressed into the delivery line.

The membrane itself can be resiliently biased in the direction of the suction stroke position. The membrane will always assume a position in which the forces acting on the membrane cancel each other out. Act the forces generated by the fluid pressure in the delivery chamber and by the resilient bias in the direction Saughubposition against the forces generated by the fluid pressure in the working space.

The pressurization of the hydraulic fluid with an oscillating pressure thus leads to an oscillating movement of the diaphragm and, associated therewith, to an oscillating pumping action of the delivery fluid from the suction line into the pressure line.

Hydraulically operated diaphragm pumps are preferably used in the conveying of conveying fluids under high pressures, since the hydraulic fluid uniformly loads the diaphragm and thus has a long service life.

In this case, the pressurization of the hydraulic fluid with the oscillating pressure usually takes place by means of a movable piston. It may happen that the amount of fluid in the working space deviates from the desired amount at a strong contamination of the suction valve or a flow around the piston. In this case, either too much hydraulic fluid may be accumulated in the working space, so that the diaphragm is deflected beyond its Druckhubposition also, or there may be too little hydraulic fluid in the working space, so that the membrane can not reach the Druckhubposition. In the first case, there is a risk of excessive strain on the diaphragm, which reduces its life and can cause damage. In the second case, the delivery volume per stroke is undesirably reduced.

Solutions to this problem are described in the prior art, for example disclosed DE 10 2013 105 072 A1 a solution according to which movement of the membrane beyond the Druckhubposition addition, a passage to a reservoir of the hydraulic fluid is released, so that the pressure in the working space is automatically reduced.

Ideally, the supply of the diaphragm pump under all load and operating conditions should be ensured in order to avoid damage to the diaphragm pumps and in particular to the membrane itself. In particular, accidents are problematic, for example, by a closed or dirty suction line may occur. In this case, there is too little or no delivery fluid in the delivery chamber. As described, the forces generated by the fluid pressure in the pumping chamber and by the resilient bias in the direction of the suction stroke position act against the forces generated by the fluid pressure in the working chamber. However, if there is no or too small amount of delivery fluid in the delivery chamber, the membrane can be deflected over the Druckhubposition, since the fluid pressure in the delivery chamber is too low.

To solve this problem, it is known in the art, for example, to resort to strong return springs. However, these have the disadvantages that a strong cavitation in the delivery chamber, which is associated with a foaming and noise, and the membrane is exposed to extreme stress, especially at the clamping points.

The object of the present invention is therefore to overcome the disadvantages of the prior art, and in particular to provide a diaphragm pump, which prevents damage to the membrane in case of failure, with a noise and foaming is preferably prevented.

This object is achieved by a diaphragm pump having a delivery chamber and a working chamber, wherein the delivery chamber comprises a pressure port and a suction port, and wherein the working space is filled or filled with a hydraulic fluid and is in operative connection with a pressure generating device to the hydraulic fluid with an oscillating pressure to be applied, further comprising a membrane having at least one membrane layer and a membrane core, which separates the delivery chamber and the working space, and which can be transferred from a Druckhubposition in a suction stroke and back again, wherein the volume of the delivery chamber in the Druckhubposition the membrane is smaller as in the suction stroke position, and wherein the membrane with a membrane retractor comprising a tie rod is engageable or is operatively connected, which can act on the membrane in the direction of the suction stroke position with a return force, and further comprise assuming a reservoir for receiving the hydraulic fluid, and wherein the working space and the storage space are connected to each other by means of a closure element closed Rückflusskanals, and wherein the closure element is in operative connection with the membrane core and the membrane return means, so that the return force and by the fluid pressure in the working space of the return force counteracting compressive force acts on the closure element, and wherein when a predetermined release force is exceeded as the sum of the return force and the pressure force on the closure element of the return flow channel is open, and wherein membrane core (15) and tie rod (19) releasably connected to each other, wherein in the connected state of membrane core (15) and tie rod ( 19), the return flow channel (25) is closed and in the non-connected state, the return flow channel (25) is opened.

The invention is based on the surprising finding that the forces acting on the membrane can be effectively limited to a predetermined value by the formation according to the invention of a closure element operatively connected to the membrane core and the membrane return device, in which a return flow channel is opened when a release force is exceeded and the fluid pressure in the working space is reduced, in which the fluid can flow from the working space into the storage space. If two forces act in opposite directions, the amount of the total force results from the fact that the larger amount of force decreases by the smaller. However, this presupposes that the forces act on the same point of attack. In the case of the diaphragm pump according to the invention, the return force engages on or in the region of the end opposite the diaphragm of the pull-back rod of the membrane return device and the pressure force acts in the region of the diaphragm. The force application points of return force and pressure force are thus according to the invention on opposite sides of the closure element, so act on the closure element itself, the addition of return force and pressure force. If this sum exceeds a predetermined release force according to the invention, the closure element is opened and the pressure force is reduced. Thus, the membrane is protected against excessive loads. The delivery pressure in the delivery chamber, on the other hand, directly counteracts the pressure force, since both forces act directly on the membrane on one side of the closure element. The pressure force is therefore reduced in its amount by acting against this force of the delivery pressure in the delivery chamber. If the delivery pressure drops abruptly in the delivery chamber, the amount of the pressure force in turn increases sharply, so that the resulting sum of pressure force and return force can be above the release force, this being initially independent of the deflection of the diaphragm between suction stroke position and Druckhubposition.

In this case, however, it may be provided, in particular, that when the diaphragm is deflected beyond the pressure stroke position from the suction stroke position, the closure element and the return flow channel are open. It can be provided that the closure element is formed by the membrane core.

To generate the return force, spring elements are preferably used according to the invention. If the diaphragm is moved away from the suction stroke position via the pressure stroke position, the return force of the spring element acting in the direction of the suction stroke position increases. At the same time, the compressive force counteracting the return hollow force and produced by the fluid in the working space and acting on the membrane in the opposite direction increases. By suitable selection of the release force, the maximum deflection of the membrane can thus be determined. This can also be done independently of the delivery pressure in the delivery chamber according to an embodiment of the present invention.

According to one embodiment of the present invention, it has proved to be particularly advantageous that the return flow channel runs in sections in the membrane return device.

According to the invention, the closure element is in operative connection with the membrane core and the membrane return device. It has been shown that the reflux channel runs in a particularly suitable manner in sections in the membrane return device, so that an integrated solution of membrane core, membrane return device, closure element and Reflux channel can be provided. This embodiment has proven to be particularly compact and reliable.

According to this preferred embodiment, membrane core and drawbar together form the closure element. Both are releasably connected to each other, wherein the compound is released only when the release force is exceeded. Once the connection has been achieved, the working fluid can flow into the storage space through the return flow channel, which is preferably partially integrated into the drawbar, so that the pressure in the working space is reduced.

According to one embodiment of the present invention, it may be preferable for the closure element to comprise and / or be in contact with a magnet, the direction and strength of the magnetic force corresponding to the predetermined release force and the return flow channel being open when the release force is exceeded.

According to the invention, it may be provided that the membrane core comprises a magnet which is in operative connection with the pull rod of the membrane return device and which is designed and arranged to hold the membrane core in contact with the pull rod until the release force is exceeded. If the release force is exceeded, the membrane core is released from the pull rod and both elements are separated. In this state, the reflux channel, which is preferably integrated in the pull rod, is open and the working fluid can flow into the reservoir, so that the pressure in the working chamber and thus the pressure force are reduced.

A magnetic connection of membrane core and tie rod according to the invention has the particular advantage that a reversible solution is provided. As soon as the release force is undershot, membrane core and tie rod can reconnect and the membrane pump according to the invention can continue to operate without the membrane being damaged.

It can of course also be provided that the magnet is comprised by the pull rod, by another element of the membrane return device and / or a further element of the diaphragm pump.

Alternatively, it can also be provided that the closure element comprises a predetermined breaking point as overload protection, which resists the triggering force until it exceeds the same and breaks when the triggering force is exceeded and the return flow channel is open.

Such a predetermined breaking point as part of the connection of membrane head and pull rod prevents reincorporation of the same and thus leads to the fact that in the event of a protective event occurring for the membrane, the corresponding component must be replaced before restarting.

It can also be provided that the working space is arranged in a housing, wherein the return flow channel runs in sections through the housing in the region of the drawbar.

Usually, the working space of a diaphragm pump according to the invention is separated from the storage space by means of a housing. To provide the return flow channel, which allows the working fluid to flow from the working space into the storage space, it must forcibly pass through said housing. It has proved to be particularly favorable according to the invention, when the return flow channel, which runs in sections in the pull rod, is continued in the region of the housing adjacent to the pull rod. As a result, it is possible to dispense with hoses, lines and the like, so that an efficient and reliable solution is provided.

In this case, it may be particularly preferred for the membrane return device to be guided in sections through a region of the housing designed as a guide section, wherein the return flow channel has an elongated connection section along its deflection of the membrane return device on its side facing the membrane return device, so that the membrane return device is independent of the deflection position of the membrane return device are located in the membrane return device located portion of the return flow channel and located in the housing portion of the return flow channel in operative connection.

By such an inventive design of a return flow channel is made possible that no hoses, pipes or the like for a connection required in the drawbar portion of the return flow channel and located in the housing portion of the return flow channel. Rather, regardless of the deflection of the membrane return device, a secure connection of the portion of the return flow channel running in the latter with the stationary section running in the housing is made possible.

Furthermore, it can be provided that the pull rod is in operative connection with a spring element, so that the diaphragm is biased springs in the direction of the suction stroke.

It has proven to be advantageous to resort to providing the return force on a spring element which is connected to the opposite end of the diaphragm of the pull rod.

It may be particularly advantageous that the deflection of the pull rod is limited by means of a fixed stop, so that the pull rod is not moved from the suction position on the Druckhubposition or a predetermined position farther from the suction stroke position than the Druckhubposition also movable.

This has the particular advantage that in the case of a slowly occurring overfilling, for example by an increasingly dirty suction line, a maximum deflection of the membrane can be fixed. If the membrane is laid over this point, the sum of return force and compressive force increases significantly and the reflux channel is opened.

Also, it has proved to be advantageous that the working space and the storage space are connected to each other via a closed with a further closure element return flow channel, wherein the further closure element is connected relative to the pull rod movable therewith, so that the further closure element from a closed position into a Opening position and back can be transferred, and wherein the further closure element comprises a force-generating element and / or is operatively connected thereto, which locks the further closure element in the closed position, and wherein the further closure element transferred to the open position and the further return channel is open when For the pressure difference between the pressure in the reservoir p ₂ and the pressure in the working space p ₁ is p ₂ - p ₁ > a, where a is a predetermined pressure.

It can be provided that the further return channel runs in sections in the membrane return device, in particular in the pull rod, and wherein the further return channel is preferably connected to the return flow channel.

Thus, it can be ensured that in the event of fluid loss in the working space, fluid can be replenished from the storage space as soon as the pressure in the working space falls below a predetermined value.

It is particularly advantageous that according to the invention the leakage compensation is integrated directly into the membrane return device and can be in operative connection with the same return flow channel, so that the number of openings through the housing is minimized. Each connection extending through the housing is associated with the risk of a lack of tightness, in particular at high pressures in the working space, so that as closed a housing as possible is generally preferred.

Further features and advantages of the invention will become apparent from the following description in which embodiments of the invention with reference to schematic drawings is exemplified, without thereby limiting the invention.

Fig. 1:

eine seitliche Schnittansicht einer Ausführungsform einer erfindungsgemäßen Membranpumpe;

Fig. 2:

eine seitliche Schnittansicht der Ausführungsform einer erfindungsgemäßen Membranpumpe gemäß Fig. 1;

Fig. 3:

eine weitere seitliche Schnittansicht einer Ausführungsform einer erfindungsgemäßen Membranpumpe gemäß den Fig. 1 und 2;

Fig. 4:

eine seitliche Schnittansicht einer alternativen Ausführungsform einer erfindungsgemäßen Membranpumpe; und

Fig. 5:

eine seitliche Schnittansicht einer weiteren Ausführungsform einer erfindungsgemäßen Membranpumpe.

Showing:

Fig. 1:

a side sectional view of an embodiment of a diaphragm pump according to the invention;

Fig. 2:

a side sectional view of the embodiment of a diaphragm pump according to the invention according to Fig. 1 ;

3:

a further sectional side view of an embodiment of a diaphragm pump according to the invention according to the Fig. 1 and 2 ;

4:

a side sectional view of an alternative embodiment of a diaphragm pump according to the invention; and

Fig. 5:

a side sectional view of another embodiment of a diaphragm pump according to the invention.

In FIG. 1 an embodiment of a membrane pump 1 according to the invention with a delivery chamber 3 and a working space 5 is shown by way of example. The delivery chamber 3 in this case has a pressure connection 7 and a suction connection 9. In this case, the delivery chamber 3 is separated from the working space 5 by means of a membrane 11.

The working space 5 is filled with a hydraulic fluid and communicates with a pressure generating device, not shown, in operative connection to pressurize the hydraulic fluid with an oscillating pressure.

The membrane 11 has at least one membrane layer 13 and a membrane core 15, wherein the membrane 11 can be transferred from a pressure stroke position into a suction stroke position and back again.

As in FIG. 2 shown is the volume of the delivery chamber 3 in the Druckhubposition the membrane 11 is smaller than in the suction stroke position. The usual deflection of the membrane is labeled D.

The membrane 11 is also connected to a membrane retractor 17 comprising a pull rod 19, which acts on the membrane 11 in the direction of the suction stroke position with a return force.

Furthermore, a storage space 21 for receiving the hydraulic fluid is shown, wherein the working space 5 and the storage space 21 are connected to one another by means of a closed by means of a closure element 23 return flow channel 25.

As in FIG. 3 can be seen, the diaphragm core 15 and the pull rod 19 are detachably connected to each other, wherein in the connected state of membrane core 15 and tie rod 19 of the return flow channel 25 is closed and in the non-connected state, the return flow channel 25 is opened, so that in the in FIGS. 1 to 3 shown embodiment of the present invention, the membrane core 15 together with the pull rod 19, the closure element 23rd forms, with a secure connection is provided by means of a magnet 27.

The magnet 27 is designed and arranged to hold the connection between the membrane core 15 and pull rod 19 until a release force is exceeded. On the compound of membrane core 15 and tie rod 19, which together form the closure element, acts on the one hand, the return force R, which acts through the spring element 39 at the opposite end of the diaphragm 19 of the pull rod. The return force R counteracts the amount of the pressure force D and the delivery pressure F of the delivery fluid in the delivery chamber 3. The pressure force D acts on that end of the tie rod 19, which faces the membrane 11. Thus acts on the connection of the membrane core 15 and tie rod 19, the sum of compressive force D and return force R.

Furthermore, in the FIGS. 1 to 3 shown that the membrane retractor 17 is partially guided by a portion formed as a guide portion 35 of the housing. In this guide section 35, the return flow channel 25 has, at its side facing the membrane retraction device 17, an elongated connection section 37 along the deflection of the membrane retraction device 17.

This elongate connecting section 37 serves to ensure that, independently of the deflection position of the membrane return device 17, the section of the return flow channel 25 located in the membrane return device 17 and the section of the return flow channel 25 located in the housing are in operative connection, so that the connection between the working space 3 at any time and the storage space 21 can be produced.

An alternative embodiment of the present invention is in FIG. 4 represented, which differs from the embodiment according to the FIGS. 1 to 3 differs in that is used to connect the membrane core 15 and tie rod 19 to a predetermined breaking point 33.

Another embodiment is in FIG. 5 shown. At the in FIG. 5 Shown embodiment, a leakage compensation device is supplemented. For the work space 5 and the storage space 21 via one with another Closing element 41 closed return flow channel 43 connected to each other. The further closure element 41 is connected relative to the pull rod 19 movable with this, so that the further closure element 41 can be transferred from a closed position to an open position and back.

The further closure element 41 is in this case in operative connection with a force-generating element 45, which in the embodiment according to FIG FIG. 5 is formed in the form of a spring element. Here, the further closure member 41 is locked in the closure position and is transferred into the opening position, so that the further return flow channel 43 is opened when the pressure difference between the pressure in the reservoir p ₂ and the pressure in the working space p ₁ applies p ₂ - p ₁ > a, where a is a predetermined pressure.

The features of the invention disclosed in the preceding description, the claims and the drawings may be essential both individually and in any combination for the realization of the invention in its various embodiments.

Claims (13)

Diaphragm pump (1) having a delivery chamber (3) and a working chamber (5), wherein the delivery chamber (3) comprises a pressure port (7) and a suction port (9), and wherein
the working space is filled or filled with a hydraulic fluid and is operatively connected to a pressure generating device to pressurize the hydraulic fluid with an oscillating pressure, further comprising a diaphragm (11) having at least one diaphragm layer (13) and a diaphragm core (15) supporting the diaphragm Conveying chamber (3) and the working space (5) separated from each other, and which can be transferred from a Druckhubposition in a suction stroke position and back again, wherein the volume of the delivery chamber (3) in the Druckhubposition the membrane (11) is smaller than in the suction stroke position, and where
the membrane (11) can be brought into or is operatively connected to a membrane retraction device (17) comprising a pull rod (19) which can apply a return force to the membrane (11) in the direction of the suction stroke position,
and further comprising a reservoir (21) for receiving the hydraulic fluid, and wherein
the working space (5) and the storage space (21) are connected to one another by means of a closure element (23, 23 ') [23'] which is not yet closed in the figures], characterized in that the closure element (23, 23 ') with the membrane core (15) and the membrane retractor (17) is in operative connection, so that the return force and by the fluid pressure in the working space (5) of the return force counteracting compressive force on the closure element (23, 23') acts, and wherein at exceeding a predetermined release force as the sum of the return force and the pressure force on the closure element (23, 23 ') the return flow channel (25) is open, and wherein membrane core (15) and tie rod (19) releasably connected to each other, wherein in the connected state of the membrane core (15) and pull rod (19) of the return flow channel (25) is closed and in the non-connected state, the return flow channel (25) is opened. Diaphragm pump according to claim 1, characterized in that
when the membrane (11) is deflected beyond the pressure stroke position away from the suction stroke position, the closure element (23, 23 ') and the return flow channel (25) are open. Diaphragm pump according to claim 1 or claim 2, characterized in that
the return flow channel (25) extends in sections in the membrane return device (17). Diaphragm pump according to one of the preceding claims, characterized in that
the closure element (23, 23 ') is formed by the membrane core (15). Diaphragm pump according to one of the preceding claims, characterized in that
the return flow channel (25) extends in sections in the pull rod (19) of the membrane return device (17). Diaphragm pump according to one of the preceding claims, characterized in that
the closure element (23, 23 ') comprises and / or is in operative connection with a magnet (27), the direction and strength of the magnetic force corresponding to the predetermined release force and, when the force exceeds the limit value Release force of the return flow channel (25) is opened. Diaphragm pump according to one of claims 1 to 6, characterized in that
the closure element (23, 23 ') comprises a predetermined breaking point (33) as overload protection, which resists the triggering force and breaks when the triggering force is exceeded and the return flow channel (25) is open. Diaphragm pump according to one of the preceding claims, characterized in that
the working space is arranged in a housing, wherein the return flow channel (25) runs in sections through the housing in the region of the pull rod (19). Diaphragm pump according to claim 8, characterized in that
the diaphragm return device (17) is guided in sections through a region of the housing designed as a guide section (35), the return flow channel (25) having an elongate connecting section (37) along its deflection of the membrane return device (17) along its side facing the membrane return device (17) in that, irrespective of the deflection position of the membrane return device (17), the section of the return flow channel (25) located in the membrane return device (17) and the section of the return flow channel (25) located in the housing are in operative connection. Diaphragm pump according to one of the preceding claims, characterized in that
the pull rod (19) is in operative connection with a spring element (39), so that the diaphragm (11) is prestressed in the direction of the suction stroke Diaphragm pump according to one of the preceding claims, characterized in that
the deflection of the pull rod (19) is limited by means of a fixed stop, so that the pull rod (19) is not movable from the suction stroke position beyond the push stroke position or a predetermined position farther from the suction stroke position than the push stroke position Diaphragm pump according to one of the preceding claims, characterized in that
the working space (5) and the storage space (21) are connected to one another via a return flow channel (43) closed by a further closing element (41), wherein the further closing element (41) is movably connected thereto, relative to the draw bar (19) in that the further closure element (41) can be transferred from a closed position into an open position and back, and wherein the further closure element (41) comprises and / or is in operative connection with a force-generating element (45) which engages the further closure element (41) in the locking position locks, and wherein the further closure member (41) into the opening position and the additional return flow channel (43) is opened when the pressure difference between the pressure in the reservoir p ₂ and the pressure in the working space p ₁ applies p ₂ - p ₁ > a, where a is a predetermined pressure. Diaphragm pump according to claim 11 or 12, characterized in that
the further return channel (43) runs in sections in the membrane return device (17), in particular in the pull rod (19), and wherein the further return channel (43) is preferably connected to the return channel (25).

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